(function ($){
    var common = $.common = {};
    $.fn.extend(common, {
        trim: function (str){
            let str1 = str || '';
            return str.trim(str1);
        }
    });
})(jQuery);
// console.log(jQuery)
// console.log($.common)
// console.log($.common.trim)
// console.log($.common.trim("good "))